Examples of a variable valve mechanism include a variable valve mechanism 90 developed by the applicant of the present invention and illustrated in FIG. 11 and FIGS. 12A and 12B (Patent Document 1). This variable valve mechanism 90 includes a main arm 92 that is driven by a small-lift cam 91a to drive a valve 7, a first sub arm 93 that is driven by a middle-lift cam 91b to swing, and a second sub arm 94 that is driven by a large-lift cam 91c to swing. The respective sub arms 93 and 94 are each coupled to and uncoupled from the main arm 92, whereby three-stage switching is achieved.